Directional antenna system



Oct. 5, 1937. e. RENATUS ,0

DIRECTIONAL ANTENNA SYSTEM Filed Nov.- 15, 1955 INVENTOR GUSTAV RENATUS.

ATTORNEY Patented Oct. 5, 1937 UNITED STATES DIRECTIONAL ANTENNA SYSTEM Gustav Renatus, Berlin, Germany, assignor to Telefunken Gesellschaft fiir Drahtlose Telegraphic in. b. H., Berlin, Germany, a corporation of Germany Application November 15, 1935, Serial No. 49,885 In Germany November 17, 1934 '7 Claims.

The present invention relates to a'directional antenna system for radiating singularly or uniformly polarized waves and having several single radiators connected to a parallel wire connection line, and in which a reflecting surface is placed in back of the radiation plane or radiation planes.

For the directed radiation of short waves, antenna'systems are often used consisting of several single radiators connected to anenergy line (umbrella antenna, or beam). An example of the embodiment of this antenna shape is shown in Fig. 1 in which five horizontal dipoles Ha are connected to a vertical connection line Va. The antenna system may be fed from below in such manner that the energy furnished by a high-frequency transmitter is supplied across an energy line Z connected to the connection line Va. The antenna arrangement may also be fed at the electrical center point thereof across an energy line Z, for instance at the connection point of the central horizontal dipole Ha. If the same arrangement is to be used for directive reception, in place of the transmitter, a receiver is to be connected to the energy lines. I

In analyzing the radiation field of such a directional antenna, it will be found that in the arrangement shown by way of example, the radiated waves are predominantly polarized in hor- 30 izontal direction, while anot inconsiderable part with vertical polarization is also present. These vertically polarized waves originate in the vertical connection lines between the single radiators. Although these lines are relatively close to each 35 other, the relative distance thereof can no longer be neglected in the case of short waves. There results therefrom a not inconsiderable radiation with a polarization corresponding to the geometrical arrangement of said lines.

In many cases, for instance, for increasing the selectivity or for bridging obstacles (arrangements of masts, forests) oscillations polarized in one direction only are desired. In a particular case it may also be desirable to send a message or a warning signal with differently polarized radiations in various directions. In such cases it is indispensable that the radiated waves be unequivocally or uniformly polarized.

The subject matter of the present invention offers a means for attaining this end. This directional antenna system, according to the invention, is characterized by the fact that the parallel wire connection line (connection lines) of the single radiators are arranged in back of the reflecting layer, and that the single radiators are fed by means of lines extending at right angles to and through the reflecting layer- Examples of embodiments of the inventiveidea are represented in Figs. 2 to 9.

In the drawing, Fig. 1 illustrates a known type of antenna; Fig. 2 illustrates a front view of a multiple dipole antenna; system in accordance with the invention; Figs. 3, 4 and '7 illustrate side views of a system in accordance with l the invention; Figs. 5, 6a and 6b illustrate topplan views of an antenna system in accordance with the invention; Fig. 8 illustrates an airplane provided with an antenna system in accordance with the invention; and Fig. 9 illustrates a receiver equipped to receive vdiiferently polarized components of waves radiated by an antennasystem of the invention.

In order to obtain at'the radiator the same electrical conditions as before, the dipoles Ha are connected to the connection lines Vd by means of through lines S, preferably chosen M2 in length. However, through lines having the length M4 connected in the current. loop of the connection lines are also suited. The through lines may be fixedly secured in or at the reflecting layer F with sulficient insulation therebetween, and at the same time they may serve as support for the dipoles and for, the connection lines. Where it is intended to change the distance d1 of the dipoles, or thedistance (c2 of the connection lines from the reflecting surface- F, for instance at wave change, the through lines or the sections of the through lines may be adapted with varying length. This can be accomplished in a simple manner, by placingthe radiators or lines over the through lines S by means of tubular sleeves R having groove guides. Note Fig. 4. The through lines S may also be chosen of such length that at the place of fastening, there is an insulator bushing I which is located atapoint of low high-frequency potential relativeto ground; If the radiation of the connection line i'sto -be suppressed, the connection lines placed in back of the reflecting layer may be shielded, for instance in such manner that they are covered with a tubing having the radius M8, as indicated in which are at right angle to each other.

nection with a parabolic cylindrical reflector P in whose focal line the connection line is placed. Such an arrangement is shown in the Figs. 6a and 6b and '7. This arrangement may, for instance,

' be used in airplanes as approaching and warning transmitter, (Fig. 8) in such manner that a' definite signal with horizontal polarization is given in the direction of travel and that the same signal eventually slightly weaker and having.

vertical polarization is given in the direction to the point of departure. V 7

On another airplane or on the flying field, a

directionalantenna system, according tothe invention, may be used as a receiving arrangement. I

In this case the energy line of the receiver will suitably be connected in thecenter point of the parallel wire connection line, in order. to enable the antenna arrangement to be swung or turned about its electrical center point. In the operating position, the receiver arrangement will be disposed at an angle of about 45,"in order to en- 7 able the reception of components of the two directions of polarization of the transmitter, and Note Fig. 9. f In turning the receiver arrangement it can be ascertained whether the respective air craft flies away or towards the observation. point.

Such short wave directional antennas are ordinarilyset up at exposed places so that danger exists that, due towind and weather and also due to. other exterior influences, the tuning and the radiation property may'slightly change. It

is therefore advisable to surround the entire' antenna arrangement with an electrically suitable insulation material or' to embed the same therein. a 1 The idea of the present invention is not limited to the examples of construction above presented. r

What is claimed is: '1. An. antenna comprising a dipole antenna arranged in a substantially vertical plane, are 7 fleeting surface for said dipole, and a two-conductor line connected to said dipole and extendingv through said surface, the conductors of said line being arranged in a plane substantially per- V pendicular to the plane of said dipole, a twoconductor-energy feeder for said line arranged 'on the opposite side of the reflecting surface as said antenna, said pair of conductors being perpendicular to saidline and to said antenna, and

a shield tube having a radius approximately equal to one-eighth of the length of the .com-.

munication wave encircling in'part said pair of conductors. I v

3. An antenna comprising aplurality of parallel dipole antennas located substantially in the same plane, areflecting surface for said an tennas, a pair of connections for each dipole extending from the dipole through said surface and arranged at right angles to the dipole, said connections' having a length substantially equal to half the length of the communication wave, and a feeder system located on the side of said surface opposite the antennas and coupled to said connections, V

4. An antenna comprising a dipole arranged in a plane, a reflecting surface forsaid dipole, and a two-conductor line connected to said dip le and extending throughsaid surface, the con-- ductors of said line bein perpendicular' to said dipole, a feeder line'located on the side 'of said surface opposite said dipole and connected to said two-conductor line, saidfeeder line being perpendicular to said two-conductor line, and a parabolic reflector for said feeder line, said parabolic reflector being arranged to direct the ra diations from said feeder line in a direction opposite to the energy radiated fromsaid dipole.

5. An antenna comprising an antenna 'having two arms arranged in a horizontal plane, a substantially vertical plane'reflecting surface for said antenna,-a two-conductor line connected to said antenna and extending through said surface, a vertical feeder line locatedfon the, side of said plane surface opposite said'antenna and connected to said two-conductor line, and high fre-.

quency apparatus coupled to said feeder line.

6. An antenna comprising a dipole antenna arranged in a plane, a reflecting surface for said dipole, and a two-conductor line connected to said dipole and extending through said surface, the conductors of said line being arranged perpendicular to said dipoleya two-conductor energy feeder forsaid line arranged on the opposite side of the reflecting surface as said dipole antenna,

and a curved reflector on said opposite side of said surface for directing the radiations from said feeder, said feeder being located in the focal line of said curved reflector.

'7. An antenna comprising a dipole antenna ar-. ranged in a plane, a'reflecting surface for said dipole, and a two-conductor line connected to said dipole and extending through said surface, the conductors of said line being arranged in 'a plane perpendicular to the plane of said dipole,

'a two-conductor energy'feeder for said line arranged on the opposite ,sideof the reflecting surface as said dipole, and a curved reflector located on the opposite side of said surface for each conductor of said energy feeder for directing the radiations fromsaid feeder.

GUSTAV RENATUS. 

